Collective patterns arising out of spatio-temporal chaos

We present a simple mathematical model in which a time averaged pattern emerges out of spatio-temporal chaos as a result of the collective action of chaotic fluctuations. Our evolution equation possesses spatial translational symmetry under a periodic boundary condition. Thus the spatial inhomogeneity of the statistical state arises through a spontaneous symmetry breaking. The transition from a state of homogeneous spatio-temporal chaos to one exhibiting spatial order is explained by introducing a collective viscosity which relates the averaged pattern with a correlation of the fluctuations.Comment: 11 pages (Revtex) + 5 figures (postscript

Stochastic synchronization in globally coupled phase oscillators

Cooperative effects of periodic force and noise in globally Cooperative effects of periodic force and noise in globally coupled systems are studied using a nonlinear diffusion equation for the number density. The amplitude of the order parameter oscillation is enhanced in an intermediate range of noise strength for a globally coupled bistable system, and the order parameter oscillation is entrained to the external periodic force in an intermediate range of noise strength. These enhancement phenomena of the response of the order parameter in the deterministic equations are interpreted as stochastic resonance and stochastic synchronization in globally coupled systems.Comment: 5 figure

How physicians caring for adult patients presenting a chronic mental disturbance take account of the difficulties their patients’ children under 18: Preliminary study

AbstractAimsTo study how physicians caring for adult patients presenting a chronic mental disturbance take account of the difficulties of their patients’ children under 18.MethodExploratory and qualitative study based on an in-depth study of interviews.Study populationThirteen physiatrists or neurologists following brain-damaged patients and 12 psychiatrists following patients with chronic psychiatric disorders.ResultsIn the two groups of physicians, diversified practices in catering for the issues of the patient's parenthood, child–parent relationships, and difficulties experienced by the child. The child's difficulties are not approached as such. For many of the physicians, representations of the parenting function, and of the child's needs and difficulties are not often used in work with the patient. Patient-centred care appears at odds with catering for the patient's children and their specific difficulties. The seriousness of the mental pathologies, their chronic nature, and the fact that they can affect the patient in his/her parental functioning and concerns, appear as factors in the reluctance of physicians. Other reasons are lack of familiarity with issues relating to childhood, and the feeling of encroaching on a private and intimate sphere. The representations of physicians with regard to parenthood, parent–child relations, and the needs and difficulties of children, are often not integrated into the corpus of knowledge. These issues are more often aspects of physicians’ own experience.ConclusionThe conflict of values and the uneasiness of the physicians suggest the need for ethical reflection groups or Balint groups

Forecasting confined spatiotemporal chaos with genetic algorithms

A technique to forecast spatiotemporal time series is presented. it uses a Proper Ortogonal or Karhunen-Lo\`{e}ve Decomposition to encode large spatiotemporal data sets in a few time-series, and Genetic Algorithms to efficiently extract dynamical rules from the data. The method works very well for confined systems displaying spatiotemporal chaos, as exemplified here by forecasting the evolution of the onedimensional complex Ginzburg-Landau equation in a finite domain.Comment: 4 pages, 5 figure

Singularites in the Bousseneq equation and in the generalized KdV equation

In this paper, two kinds of the exact singular solutions are obtained by the improved homogeneous balance (HB) method and a nonlinear transformation. The two exact solutions show that special singular wave patterns exists in the classical model of some nonlinear wave problems

Time resolved pattern evolution in a large aperture laser

We have measured quasi-instantaneous transverse patterns in a broad aperture laser. Non-ordered patterns yielding to boundary determined regular structures in progressive time-integrated recording are observed. The linear analysis and numerical integration of the full Maxwell-Bloch equations allow us to interpret the features of the experiment. We show that this system being far from threshold cannot be fully understood with a perturbative model.Comment: 7 pages, 5 GIF figures . To be published in Phys. Rev. Let

Epigenetic Gene Promoter Methylation at Birth Is Associated With Child’s Later Adiposity

Objective: fixed genomic variation explains only a small proportion of the risk of adiposity. In animal models, maternal diet alters offspring body composition, accompanied by epigenetic changes in metabolic control genes. Little is known about whether such processes operate in humans.Research design and methods: using Sequenom MassARRAY we measured the methylation status of 68 CpGs 5? from five candidate genes in umbilical cord tissue DNA from healthy neonates. Methylation varied greatly at particular CpGs: for 31 CpGs with median methylation ?5% and a 5–95% range ?10%, we related methylation status to maternal pregnancy diet and to child’s adiposity at age 9 years. Replication was sought in a second independent cohort.Results: in cohort 1, retinoid X receptor-? (RXRA) chr9:136355885+ and endothelial nitric oxide synthase (eNOS) chr7:150315553+ methylation had independent associations with sex-adjusted childhood fat mass (exponentiated regression coefficient [?] 17% per SD change in methylation [95% CI 4–31], P = 0.009, n = 64, and ? = 20% [9–32], P < 0.001, n = 66, respectively) and %fat mass (? = 10% [1–19], P = 0.023, n = 64 and ? =12% [4–20], P = 0.002, n = 66, respectively). Regression analyses including sex and neonatal epigenetic marks explained >25% of the variance in childhood adiposity. Higher methylation of RXRA chr9:136355885+, but not of eNOS chr7:150315553+, was associated with lower maternal carbohydrate intake in early pregnancy, previously linked with higher neonatal adiposity in this population. In cohort 2, cord eNOS chr7:150315553+ methylation showed no association with adiposity, but RXRA chr9:136355885+ methylation showed similar associations with fat mass and %fat mass (? = 6% [2–10] and ? = 4% [1–7], respectively, both P = 0.002, n = 239).Conclusions: our findings suggest a substantial component of metabolic disease risk has a prenatal developmental basis. Perinatal epigenetic analysis may have utility in identifying individual vulnerability to later obesity and metabolic diseas